“More electric” vehicle architectures have been proposed to shift the primary sources used for systems and services from pneumatic (engine bleed) and hydraulic sources to electric sources. Main challenges for supporting MEA (“More Electric Aircrafts”) include not only the complexity of the level of electrical system control and coordination necessary to make the MEA workable but also envisioning technologies which meet the safety/reliability requirements of such a complex platform to be certifiable. A main concern is the fact that prior to MEA platforms, electrical power systems have historically used a distributed control scheme using a combination of electronic units and electromechanical logic to carry out the necessary functionality for electrical power distribution, protection and load management. Within this type of control scheme, the bus power controls were simple, with low criticality single channel logical controllers designed to augment existing control between the other federated system control units. The overall interaction between electrical system line replaceable units (LRU's) was limited, with the approach favoring autonomous control units that were indifferent to subtleties occurring elsewhere in the electrical system or the aircraft for that matter.
The advent of the MEA has created a situation whereby the traditional methods of electrical system control lack the sophistication necessary for the MEA. Not only is this due to the complex, critical control and protection functions being performed by the electrical power system but also the fact that the system should be able to communicate between a greater number of LRU's in order to ensure proper coordination of events. These LRU's are not only in the electrical system but also include other ATA chapter LRU's. In order to accommodate this high volume of communications and interactivity, the system design should employ high-speed processor based controls and data bus communications. Furthermore, the design should be highly flexible to account for future requirements that will only become evident as the development process of the MEA continues.
Hardware solutions based upon analog, discrete digital or even FPGA implementations of the past do not likely satisfy the flexibility and response time expected for such MEA platforms. Study of current and future aircraft equipment configurations has demonstrated that most systems on the MEA are linked in some way to the electrical power system. Therefore, as a result of the MEA, the electrical power system has become safety critical or at the very least essential to the proper functioning of systems which have traditionally had no dependency upon electricity. The key functions defining the safety of aircraft flight such as thrust, lift, stability, guidance, communications, life support and others are now significantly affected by the derivation or availability of electric power. The ability for the electrical system to perform complex management, test and reporting functions within a highly integrated aircraft environment will likely surpass any individual technology as the single largest risk factor for establishing the MEA as a viable air vehicle solution.